Hi,
Thanks for helping confirming on GCC and porting this! I'd never know
even GCC lacked this adaptation without someone actually checking... Too
many things are taken for granted these days.
On 2023/4/18 20:17, Xi Ruoyao wrote:
According to Xuerui's LLVM changeset [1], doing so can make a
significant performace gain.
Bootstrapped and regtested on loongarch64-linux-gnu. Ok for GCC 14?
[1]:https://reviews.llvm.org/D148622
gcc/ChangeLog:
* config/loongarch/loongarch.cc
(loongarch_option_override_internal): If -falign-functions is
used but the alignment is not explicitly specified, set it to
4 * loongarch_issue_rate (). Likewise for -falign-loops.
---
gcc/config/loongarch/loongarch.cc | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/gcc/config/loongarch/loongarch.cc
b/gcc/config/loongarch/loongarch.cc
index 06fc1cd0604..6552484de7c 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -6236,6 +6236,17 @@ loongarch_option_override_internal (struct gcc_options
*opts)
&& !opts->x_optimize_size)
opts->x_flag_prefetch_loop_arrays = 1;
+ /* Align functions and loops to (issue rate) * (insn size) to improve
+ the throughput of the fetching units. */
What about gating all of these on !opts->x_optimize_size, similar to
what aarch64 does?
+ char *align = XNEWVEC (char, 16);
+ sprintf (align, "%d", loongarch_issue_rate () * 4);
+
+ if (opts->x_flag_align_functions && !opts->x_str_align_functions)
+ opts->x_str_align_functions = align;
+
+ if (opts->x_flag_align_loops && !opts->x_str_align_loops)
+ opts->x_str_align_loops = align;
+
if (TARGET_DIRECT_EXTERN_ACCESS && flag_shlib)
error ("%qs cannot be used for compiling a shared library",
"-mdirect-extern-access");
Otherwise LGTM, thanks!
